package baidu;

import java.util.Arrays;
import java.util.Scanner;

public class Two {

	public static void main(String[] args) {
		Scanner scanner = new Scanner(System.in);
		int a = scanner.nextInt();
		int b = scanner.nextInt();
		int c = scanner.nextInt();
		findNumber(a, b, c);
		scanner.close();
	}

	/*public static void findNumber(long a, long b, long c) {
		List<Long> table = new ArrayList<Long>();
		int k = 0;
		// int[][] table=new int[a][b];
		for (long i = 1; i <= a; i++) {
			for (int j = 1; j <= b; j++) {
				table.add(i * j);
			}
		}
		Collections.sort(table);
		System.out.print(table.get(c-1));
	}*/
	public static void findNumber(int a, int b, int c) {
		long[] table = new long[a*b];
//		long[][] table=new long[a][b];
		int k=0;
		for (long i = 1; i <= a; i++) {
			for (int j = 1; j <= b; j++) {
				table[k++]=(i * j);
			}
		}
		Arrays.sort(table);
		System.out.print(table[c-1]);
	}
}
